I just google it. Then I read through a few of the results I get from google and see how they explain it. I never read just one, always more because they always explain it differently and getting it explained in different ways from different sources makes it stick better imo. Sometimes I also go to youtube and search for it and see if there is a video of someone explaining the grammar.
I wouldn’t actually learn how to actively use the particles. Go to How to Study Korean website and read the explanations and see how much of it sticks just by reading it.
Unfortunately I haven’t found any good books or online sources that put all the particles together and explain them all in a row (not for Korean) so you have to just go get your information from various different sources about the different particles. Or maybe do the thing Steve Kaufmann talked about on his youtube channel: He’d get some beginner textbook and read through it when starting a new language.
One thing I did in the beginning is sort of color coding sentences. (I don’t know if that’s the correct term) For example subject = red, verb = green, object = blue, time = pink a.s.o.
I’d write sentences in my notebook and then circle those parts according to my system with each corresponding color. Or if you don’t like handwriting I guess you can do that in Word or some program like that and change the font color. If you do this a few times you get used to Korean sentence structure.
One good hint I got once (which was actually for learning Japanese, but it applies to Korean as well) is to read sentences backwards, because the verb is always at the end.
하루 치 계획을 다 짜서 오셨더라고요
I didn’t know this 더라고요 ending and googled it and basically it is used if you witness or personally observe something happening or someone else doing something.
※ 오셨더라고요 = I witness/observe that someone came (I guess you know who someone is from the context)
※ 짜서 → 짜다 put together, form something → what is put together?
※ 계획을 = a plan
※ 계획을 짜다 = someone puts together / forms a plan
※ and there is 다 inbetween, it just means “all” → put together/form all the plan (form the plan completely)
※ 하루 치 = according the dictionary it means “one day’s something” → 하루 치 계확 = one day’s plan
That’s why in Korean context is important. Who is the person talking? Who are they talking about? I guess if you have the whole text where this sentence came from some things are more obvious.
개나 앵무새를 데리고 타는 게 - I don’t know about this one because technically it’s not a sentence, there is no verb at the end
something about taking a dog or a parrot somewhere
Also, finally if I don’t understand next to nothing in a sentence or text (i.e I’d have to look up every other word) it probably means it’s too difficult for me. So I’d go and look for something easier and build my vocabulary by reading things that have simpler sentence structure (shorter sentences) and then later go back and try to read that sentence or text again and find it much easier than the first time.
PS. Because a few people have mentioned Talk to Me In Korean now. If you follow them on twitter you can ask them grammar or word related questions and they’ll answer. from what i’ve seen they answer anything from beginner to advanced or at least give you a link where you can read about it.